Adolescent idiopathic scoliosis

An Examination of the Number of Adolescent Scoliotic Curves That Are Braceable at First Presentation to a Scoliosis Service

Adolescent idiopathic scoliosis (AIS) affects between 0.5% and 5.2% of adolescents and is progressive in two-thirds of cases. Bracing is an effective non-operative treatment for AIS and has been shown to prevent up to 72% of curves from requiring surgery. This paper explores the presentation of AIS in the UK and identifies who would be suitable for bracing, as per guidelines published by the Scoliosis Research Society (SRS) and British Scoliosis Society (BSS), through curve severity and skeletal maturity at presentation. There were 526 patients with AIS eligible for inclusion across three tertiary referral centres in the UK. The study period was individualised to each centre, between January 2012 and December 2021. Only 10% were appropriate for bracing via either SRS or BSS criteria. The rest were either too old, skeletally mature or had a curve size too large to benefit. By the end of data collection, 38% had undergone surgery for their scoliosis. In the UK, bracing for AIS is only suitable for a small number at presentation. Future efforts to minimise delays in specialist review and intervention will increase the number of those with AIS suitable for bracing and reduce the number and burden of operative interventions for AIS in the UK.

Posterior-only correction surgery for idiopathic scoliosis Lenke type 5c: differences of strategies and outcomes between adult patients and adolescent patients

PURPOSE

To compare radiographic parameters, and functional and surgical outcomes between lumbar adolescent idiopathic scoliosis (AIS) and lumbar adult idiopathic scoliosis (AdIS).

METHODS

A retrospective study was performed to identify Lenke 5c type AIS and AdIS patients from our scoliosis database who had undergone posterior surgical treatment for scoliosis. Preoperative and postoperative radiographic and clinical outcomes were compared between the two groups.

RESULTS

A total of 22 patients were included in AdIS group, and 44 matched patients in AIS group. AdIS group had significantly larger L3 and L4 tilt and translation than AIS group (P < 0.05). AdIS group had larger T10-L2 angle and smaller T5-T12 angle (P < 0.05). AdIS group had higher VAS scores (P < 0.05) and pain domain of SRS-22 scores (P < 0.05) as compared to AIS group. Correlation analysis demonstrated positive relationship between VAS scores and T10-L2 angle (r = 0.492, P < 0.05). AdIS group was fused longer than AIS group (P < 0.05). Cobb angle of TL/L curve was larger and correction ratio was smaller at AdIS group (P < 0.05). AdIS group still had significantly larger L3 and L4 tilt and translation than AIS group (P < 0.05). CT measurements demonstrated larger postoperative vertebral body rotation at apical vertebrae and LIV at AdIS group (P < 0.05). Vertebral correction ratio was smaller at AdIS group (P < 0.05).

CONCLUSION

Lenke 5c AdIS patients had greater preoperative and postoperative L3 and L4 tilt and translation, as well as less correction of major curve and vertebral body derotation than AIS patients. However, the incidence of adding-on was similar between the two groups.

Patients with Adolescent Idiopathic Scoliosis Have Higher Metabolic Cost during High-Intensity Interval Training

BACKGROUND

Patients with adolescent idiopathic scoliosis (AIS) are found to have a lower level of physical activity, and may have reduced exercise capacity due to spinal deformity. Previous study showed the benefits of high-intensity interval training (HIIT), named E-Fit, which is specifically designed for patients with AIS to improve musculoskeletal health and psychological well-being. To optimize the beneficial effects of training, the current study aimed to investigate the appropriate exercise intensity and metabolic demand in patients with AIS when performing E-Fit.

METHODS

In all, 22 female subjects, 10 diagnosed with AIS and 12 gender-matched healthy controls, aged between 10 and 16 years, were recruited. Subjects were instructed to perform two trials of a seven min E-Fit. Breath-by-breath gas exchange parameters including oxygen consumption (VO₂), heart rate (HR) and the rate of perceived exertion (PRE) were measured during exercise. Demographic data and clinical features of AIS and body composition were obtained. Metabolic demand between AIS and control groups was compared using MANOVA with covariates adjustment.

RESULTS

Patients with AIS had an earlier onset of menarche (p = 0.01), higher visceral adipose tissue (p = 0.04) and percentage body fat (p = 0.03) as compared to controls. Patients with AIS showed a significantly higher adjusted means of VO₂ average in both the first (p = 0.014) and second trials (p = 0.011) of E-Fit. The adjusted mean of the highest measured VO₂ was higher than healthy controls and reached statistical significance in the second trial (p = 0.004). Both the AIS and control group exercised at a similar percentage of VO₂ peak (64.26% vs. 64.60%).

CONCLUSION

Patients with AIS showed higher oxygen consumption during E-Fit than heathy controls, which might indicate a higher metabolic cost. Patients with AIS could carry out exercise at a moderate exercise intensity similar to that of healthy controls, but special considerations in designing an exercise program, such as frequent rest intervals, would be useful to avoid fatigue among patients with AIS.

Understanding the Lenke Classification for Adolescent Idiopathic Scoliosis (AIS)

For over 20 years, the Lenke classification has been used as a standard to describe and classify scoliosis patterns in patients with adolescent idiopathic scoliosis (AIS). Based on this classification, patients are given a treatment recommendation, which is usually surgical. The Lenke classification has proven to be a reliable and reproducible classification for patients with AIS; however, it still proves to be complex in daily clinical practice. This study presents a simple approach to the Lenke classification for AIS patients that is easier to understand and to apply.

Risk factors associated with low bone mineral density in children with idiopathic scoliosis: a scoping review

BACKGROUND

Children with idiopathic scoliosis (IS) have a high risk of osteoporosis and IS with low bone mineral density (BMD) are susceptible to curve progression. This review aims to explore the risk factors of low BMD in children with IS.

METHODS

Studies were retrieved from 5 databases that were published up to January 2022. Search terms are keywords in titles or abstracts, including subject headings related to "Scoliosis", "Bone Mineral Density", and "Risk Factors". Observational studies on risk factors of low BMD in children with IS were enrolled in this review. The number of studies, sample size, outcome measures, research type, endocrine, and lifestyle-related factors, gene/signal pathway, and other contents were extracted for qualitative analysis.

RESULTS

A total of 56 studies were included in this scoping review. Thirty studies involved genetic factors that may affect BMD, including the Vitamin-D receptor gene, RANK/RANKL signal pathway, the function of mesenchymal stem cells, Runx2, Interleukin-6 (IL-6), and miR-145/β-catenin pathway. Eight studies mentioned the influence of endocrine factors on BMD, and the results showed that serum levels of IL-6, leptin and its metabolites, and ghrelin in children with IS were different from the age-matched controls. In addition, there were 18 articles on lifestyle-related factors related to low BMD in children with IS, consisting of physical activity, calcium intake, Vitamin D level, and body composition.

CONCLUSIONS

Genetic, endocrine, and lifestyle-related factors might relate to low BMD and even osteoporosis in IS. To prevent osteoporosis, the effectiveness of regular screening for low BMD risk factors in children with IS needs to be investigated. Additionally, clear risk factors suggest strategies for bone intervention. Future studies should consider the effectiveness of calcium and vitamin D supplements and physical activity in BMD improvement.

Clinical features and molecular characterization of Chinese patients with FKBP10 variants

BACKGROUND

Osteogenesis imperfecta (OI) is a group of rare skeletal dysplasia. Long bone deformity and scoliosis are often associated with progressively deforming types of OI. FKBP65 (encoded by FKBP10, OMIM *607063) plays a crucial role in the processing of type I procollagen. Autosomal recessive variants in FKBP10 result in type XI osteogenesis imperfecta.

METHODS

Patients diagnosed with OI were recruited for a genetic test. RT-PCR and Sanger sequencing were applied to confirm the splicing defect in FKBP10 mRNA with the splice-site variant. The bone structure was characterized by Goldner's trichrome staining. Bioinformatic analyses of bulk RNA sequencing data were performed to examine the effect of the FKBP10 variant on gene expression.

RESULTS

Here we reported three children from a consanguineous family harboured a homozygous splice-site variant (c.918-3C > G) in FKBP10 intron and developed long bone deformity and early onset of scoliosis. We also observed frequent long bone fractures and spinal deformity in another 3 OI patients with different FKBP10 variants. The homozygous splicing variant identified in the fifth intron of FKBP10 (c.918-3C > G) led to abnormal RNA processing and loss of FKBP65 protein and consequently resulted in aberrant collagen alignment and porous bone morphology. Analysis of transcriptomic data indicated that genes involved in protein processing and osteoblast differentiation were significantly affected in the patient-derived osteoblasts.

CONCLUSION

Our study characterized the clinical features of OI patients with FKBP10 variants and revealed the pathogenesis of the c.918-3C > G variant. The molecular analyses helped to gain insight into the deleterious effects of FKBP10 variants on collagen processing and osteoblast differentiation.

A Genetic Variant of the ROBO3 Gene is Associated With Adolescent Idiopathic Scoliosis in the Chinese Population

STUDY DESIGN

A case-control association study.

OBJECTIVES

This study aimed to reveal whether mutations within roundabout receptor 3 ( ROBO3 ) gene were related to adolescent idiopathic scoliosis (AIS) in Chinese Han population and to investigate the functional role of ROBO3 in the pathogenesis and progression of AIS.

SUMMARY OF BACKGROUND DATA

ROBO3 is essential for the regulation of hindbrain axonal cell migration and midline crossing. Studies have demonstrated that ROBO3 homozygous mutations are associated with horizontal gaze palsy with progressive scoliosis. However, whether and how ROBO3 contributed to the development of scoliosis remains unclear.

MATERIALS AND METHODS

Whole exome sequencing was performed in 135 AIS patients and 267 healthy controls to evaluate the differences of single nucleotide polymorphism variants within ROBO3 . Then the identified variant of ROBO3 was genotyped in another cohort included 1140 AIS patients and 1580 controls. Moreover, paraspinal muscles were collected from 39 AIS patients and 45 lumbar disk herniation patients for the measurement of ROBO3 mRNA expression. The χ 2 test, Fisher exact test or the Student t test were used to compare intergroup data. Pearson correlation was used to determine the association between ROBO3 expression and clinical phenotypes.

RESULTS

A significant association was identified between the gene variant (rs74787566) of ROBO3 and the development of AIS through exome sequencing. The genotyping cohort demonstrated a higher frequency of allele A in AIS patients compared to controls (7.89% vs . 4.30%, P <0.001, odds ratio=1.87). In addition, the expression of ROBO3 in paraspinal muscles was inversely correlated with the Cobb angle ( P =0.043, r2 =0.1059).

CONCLUSION

A significant association was identified between the gene variant (rs74787566) of ROBO3 and the development of AIS. The reduced expression of ROBO3 could result in the progression of curve magnitude in patients with AIS. Further studies are needed to verify the functional role of ROBO3 in the development of AIS.

LEVEL OF EVIDENCE

Level III.

Design and position control of a robotic brace dedicated to the treatment of scoliosis

This paper’s content focuses on designing and prototyping a robotic brace dedicated to treating scoliosis. Scoliosis is an abnormal spinal curvature affecting 1–3% of children and constitutes a major therapeutic problem. In moderate cases of deformity, passive brace treatment is performed. However, this approach can lead to important patient discomfort. So, we propose a robotic solution providing greater mobility and the possibility of adapting the procedure to each patient. The robotic brace we built and tested is composed of three specific rings adapted to the patient’s torso. Each independent module of two consecutive rings is movable through a Stewart–Gough platform-type mechanism. As the robotic brace is lightweight, it brings better portability and improves the patient’s comfort.

The first part of the paper shows the state of the art of bracing techniques: from passive to active orthoses. Next, the mechatronics of the device is detailed, and the robot’s kinematic models are developed. The motion control principle is given. In the last part, motion tests were administered with a healthy human to validate the brace architecture choice and its position and motion control strategies.

Spinal Manual Therapy for Adolescent Idiopathic Scoliosis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Objective

We conducted this meta-analysis to provide better evidence of the efficacy of manual therapy (MT) on adolescent idiopathic scoliosis (AIS).

Methods

All RCTs of MT for the management of patients with AIS were included in the present study. The treatment difference between the experimental and control group was mainly MT. The outcomes consisted of the total effective rate, the Cobb angle, and Scoliosis Research Society-22 (SRS-22) questionnaire score. Electronic database searches were conducted from database inception to July 2022, including the Cochrane Library, PubMed, Web of Science, Embase, Wanfang Data, CNKI, and VIP. The pooled data were analyzed using RevMan 5.4 software.

Results

Four RCTs with 213 patients in the experimental group were finally included. There are 2 studies of standalone MT in the experimental group and 3 studies of MT with identical conservative treatments in the control group. Three trials reported total effective rate, and a statistically significant difference was found (P = 0.004). Three trials reported Cobb angle, and a statistical difference was found (P = 0.01). Then, sensitivity analysis showed that there was a significant difference in the additional MT subgroup (P < 0.00001) while not in the standalone MT subgroup (P = 0.41). Three trials reported SRS-22 scores (P = 0.55) without significant differences.

Conclusion

There is insufficient data to determine the effectiveness of spinal manipulation limited by the very low quality of included studies. High-quality studies with appropriate design and follow-up periods are warranted to determine if MT may be beneficial as an adjunct therapy for AIS. Currently, there is no evidence to support spinal manipulation.

Patient-specific finite element modeling of scoliotic curve progression using region-specific stress-modulated vertebral growth

PURPOSE

This study describes the creation of patient-specific (PS) osteo-ligamentous finite element (FE) models of the spine, ribcage, and pelvis, simulation of up to three years of region-specific, stress-modulated growth, and validation of simulated curve progression with patient clinical angle measurements.

RESEARCH QUESTION

Does the inclusion of region-specific, stress-modulated vertebral growth, in addition to scaling based on age, weight, skeletal maturity, and spine flexibility allow for clinically accurate scoliotic curve progression prediction in patient-specific FE models of the spine, ribcage, and pelvis?

METHODS

Frontal, lateral, and lateral bending X-Rays of five AIS patients were obtained for approximately three-year timespans. PS-FE models were generated by morphing a normative template FE model with landmark points obtained from patient X-rays at the initial X-ray timepoint. Vertebral growth behavior and response to stress, as well as model material properties were made patient-specific based on several prognostic factors. Spine curvature angles from the PS-FE models were compared to the corresponding X-ray measurements.

RESULTS

Average FE model errors were 6.3 ± 4.6°, 12.2 ± 6.6°, 8.9 ± 7.7°, and 5.3 ± 3.4° for thoracic Cobb, lumbar Cobb, kyphosis, and lordosis angles, respectively. Average error in prediction of vertebral wedging at the apex and adjacent levels was 3.2 ± 2.2°. Vertebral column stress ranged from 0.11 MPa in tension to 0.79 MPa in compression.

CONCLUSION

Integration of region-specific stress-modulated growth, as well as adjustment of growth and material properties based on patient-specific data yielded clinically useful prediction accuracy while maintaining physiological stress magnitudes. This framework can be further developed for PS surgical simulation.

Abnormal morphological features of osteocyte lacunae in adolescent idiopathic scoliosis: A large-scale assessment by ultra-high-resolution micro-computed tomography

AIM

Abnormal osteocyte lacunar morphology in adolescent idiopathic scoliosis (AIS) has been reported while the results were limited by the number of osteocyte lacunae being quantified. The present study aimed to validate previous findings through (a) comparing morphological features of osteocyte lacunae between AIS patients and controls in spine and ilium using a large-scale assessment, and (b) investigating whether there is an association between the acquired morphological features of osteocyte lacunae and disease severity in AIS.

METHOD

Trabecular bone tissue of the facet joint of human vertebrae on both concave and convex sides at the apex of the scoliotic curve were collected from 4 AIS and 5 congenital scoliosis (CS) patients, and also at the same anatomic site from 3 non-scoliosis (NS) subjects intraoperatively. Trabecular bone tissue from ilium was obtained from 12 AIS vs 9 NS subjects during surgery. Osteocyte lacunae were assessed using ultra-high-resolution micro-computed tomography. Clinical information such as age, body mass index (BMI) and radiological Cobb angle of the major curve were collected.

RESULTS

There was no significant difference between density of osteocyte lacuna and bone volume fraction (BV/TV) between groups. A total of 230,076 and 78,758 osteocyte lacunae from facet joints of apical vertebra of scoliotic curve and iliac bone were included in the analysis, respectively. In facet joint bone biopsies, lacunar stretch (Lc.St) was higher, and lacunar equancy (Lc.Eq), lacunar oblateness (Lc.Ob), and lacunar sphericity (Lc.Sr) were lower in AIS and CS groups when compared with NS group. CA side was associated with higher Lc.St when compared with CX side. In iliac bone biopsies, Lc.Ob was higher and lacunar surface area (Lc.S) was lower in AIS group than NS group. Median values of Lc.St, Lc.Eq and Lc.Sr were significantly associated with radiological Cobb angle with adjustment for age and BMI (R-squared: 0.576, 0.558 and 0.543, respectively).

CONCLUSIONS

This large-scale assessment of osteocyte lacunae confirms that AIS osteocyte lacunae are more oblate in iliac bone that is less influenced by asymmetric loading of the deformed spine than the vertebrae. Shape of osteocyte lacunae in iliac bone is associated with radiological Cobb angle of the major curve in AIS patients, suggesting the likelihood of systemic abnormal osteocyte morphology in AIS. Osteocyte lacunae from concave side of scoliotic curves were more stretched in both AIS and CS groups, which is likely secondary to asymmetric mechanical loading.

Effect of muscle fatigue of the thoracic erector spinae on neuromuscular control when performing the upper extremity functional tasks in people with adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) disrupts spinal alignment and increases the intrinsic demand for active stabilization to maintain postural stability. Understanding the paraspinal muscle fatigability and its effects on spinal alignment and kinematics informs the importance of paraspinal muscle endurance for postural stability. This study aims to investigate the effects of fatigue of thoracic erector spinae on the spinal muscle activity and spinal kinematics in individuals with scoliosis. Spinal muscle activity, posture and mobility measured by electromyography and surface tomography were compared between 15 participants with scoliosis and 15 age- and gender-matched healthy controls during unilateral shoulder flexion and abduction with and without holding a 2-kg weight and performed before and after a fatigue task (prone isometric chest raise). No between-groups difference was found for the spinal extensor endurance. Erector spinae activity at the convex side of AIS group was significantly higher than that at their concave side and than that of healthy controls during shoulder elevations, regardless of the fatigue status. Significant decreases in translational and rotational mobility were found at convex side of AIS group during weighted abduction tasks after fatigue. In contrast, a significant increase in rotational mobility was demonstrated at convex side of AIS participants during weighted flexion tasks after fatigue. Our results revealed a comparable level of spinal extensor endurance between individuals with or without AIS. The increase in muscle activation post-fatigue provides no additional active postural stability but may increase the risk of back pain over the convex side in individuals with scoliosis. Findings highlight imbalances in muscles and the potential implications in optimising neuromuscular activation and endurance capacity in the rehabilitation for AIS patients. Future research is needed to investigate if endurance training of the convex-sided back extensors could optimize the impaired neuromuscular control in the AIS patients.

Effects of balance training combined with Schroth therapy on adolescents with mild idiopathic scoliosis: A six-week randomized controlled trial

BACKGROUND

Adolescent idiopathic scoliosis (AIS) has a great negative impact on the physical and mental health of patients; thus, a range of effective, timely interventions are urgently needed. Currently, there is a lack of evidence to illustrate the effect of balance training in patients with AIS, and the traditional AIS therapy often ignores the recovery in balance function of patients with AIS.

OBJECTIVE

To investigate the effect of balance training combined with Schroth therapy among adolescent with mild idiopathic scoliosis.

METHODS

59 adolescents (aged 10 to 18, 35.59% male) with idiopathic scoliosis were selected and divided into an intervention group (n= 30) and a control group (n= 29). Participants in both groups received routine rehabilitation treatment based on Schroth therapy, and balance training was added in the intervention group. The duration of treatment for both groups was 6 weeks. The Trunk Rotation Angle (ATR), Cobb angle, Scoliosis Research Society 22 (SRS-22) scale and balance function of the two groups were evaluated at baseline and after the intervention.

RESULTS

No significant difference of outcomes were observed between groups at baseline (P> 0.05). After 6 weeks of intervention, the ATR, Cobb angle, SRS-22 and balance function of the two groups improved significantly compared with those before treatment (P< 0.05), and the intervention group had a significant improvement than the control group (P< 0.05).

CONCLUSION

Balance training combined with Schroth therapy for adolescents with mild idiopathic scoliosis can significantly improve ATR, Cobb angle and quality of life, as well as overall balance function.

Bone mineral density in children and young adults with idiopathic scoliosis: a systematic review and meta-analysis

PURPOSE

Osteoporosis is a risk factor for idiopathic scoliosis (IS) progression, but it is still unclear whether IS patients have bone mineral density (BMD) loss and a higher risk of osteoporosis than asymptomatic people. This systematic review aims to explore the differences in BMD and prevalence of osteoporosis between the IS group and the control group.

METHODS

We searched 5 health science-related databases. Studies that were published up to February 2022 and written in English and Chinese languages were included. The primary outcome measures consisted of BMD z score, the prevalence of osteoporosis and osteopenia, and areal and volumetric BMD. Bone morphometry, trabecular microarchitecture, and quantitative ultrasound measures were included in the secondary outcome measures. The odds ratio (OR) and the weighted mean difference (WMD) with a 95% confidence interval (CI) were used to pool the data.

RESULTS

A total of 32 case-control studies were included. The pooled analysis revealed significant differences between the IS group and the control group in BMD z score (WMD -1.191; 95% CI  - 1.651 to -0.732, p  <  0.001). Subgroup analysis showed significance in both female (WMD -1.031; 95% CI -1.496 to -0.566, p  <  0.001) and male participants (WMD -1.516; 95% CI -2.401 to -0.632, p  =  0.001). The prevalence of osteoporosis and osteopenia in the group with IS was significantly higher than in the control group (OR  =  6.813, 95% CI 2.815-16.489, p  <  0.001; OR 1.879; 95% CI 1.548-2.281, p  <  0.000). BMD measures by dual-energy X-ray absorptiometry and peripheral quantitative computed tomography showed a significant decrease in the IS group (all p  <  0.05), but no significant difference was found in the speed of sound measured by quantitative ultrasound between the two groups (p > 0.05).

CONCLUSION

Both the male and female IS patients had a generalized lower BMD and an increased prevalence of osteopenia and osteoporosis than the control group. Future research should focus on the validity of quantitative ultrasound in BMD screening. To control the risk of progression in IS patients, regular BMD scans and targeted intervention are necessary for IS patients during clinical practice.

Effects of Posterior Spinal Correction and Fusion on Postural Stability in Patients with Adolescent Idiopathic Scoliosis

The present study aimed to assess the effects of posterior spinal correction and fusion on postural stability in patients with adolescent idiopathic scoliosis (AIS). The study included 41 female patients with AIS at our institution. All patients performed three 10 s single-leg standing trials on a force plate. The center of pressure (COP) was measured preoperatively, and at 1 week and 6 months postoperatively. The postural stability parameters were absolute minimum time-to-boundary (TTB), mean of the minimum TTB, mean COP velocity, standard deviation, range, and 95% confidence ellipse area. One-way repeated analysis of variance or Friedman test was applied to the postural stability parameters. Multiple comparisons were performed using the Bonferroni correction. The absolute minimum TTB and the mean minimum TTB showed a significant increase 6 months post-operation as compared to preoperatively and 1 week postoperatively. The COP velocity significantly decreased at 6 months post-operation compared to preoperatively and 1 week postoperatively. These changes in postural stability indicate that spinal correction and fusion can be considered to improve postural stability during single-leg standing tests in the postoperative period.

Whole-Exome Sequencing Identifies Genetic Variants for Severe Adolescent Idiopathic Scoliosis in a Taiwanese Population

Adolescent idiopathic scoliosis (AIS) is a three-dimensional spinal curvature deformity that appears in the adolescent period. In this study, we performed whole-exome sequencing on 11 unrelated Taiwanese patients with a Cobb's angle greater than 40 degrees. Our results identified more than 200 potential pathogenic rare variants, however, most of which were carried only by one individual. By in silico pathogenicity annotation studies, we found that TTN, CLCN1, and SOX8 were the most important genes, as multiple pathogenic variants were within these genes. Furthermore, biological functional annotation indicated critical roles of these AIS candidate genes in the skeletal muscle. Importantly, a pathogenic variant on SOX8 was shared by over 35% of the patients. These results highlighted TTN, CLCN1, and SOX8 as the most likely susceptibility genes for severe AIS.

Construction of the Adjusted Scoliosis 3D Finite Element Model and Biomechanical Analysis under Gravity

OBJECTIVE

Adolescent idiopathic scoliosis (AIS) is a three-dimensional structural deformity of the spine caused by the disruption of the biomechanical balance of the spine. However, the current biomechanical modeling and analysis methods of scoliosis cannot really describe the real state of the spine. This study aims to propose a high-precision biomechanical modeling and analysis method that can reflect the spinal state under gravity and provide a theoretical basis for therapeutics.

METHODS

Combining CT and X-ray images of AIS patients, this study constructed an adjusted three-dimensional model and FE model of the spine corresponding to the patient's gravity position, including vertebral bodies, intervertebral discs, ribs, costal cartilage, ligaments, and facet cartilage. Then, the displacement and stress of the spine under gravity were analyzed.

RESULTS

A model of the T1-Sacrum with 1.7 million meshes was constructed. After adding the gravity condition, the maximum displacement point was at T1 of thoracic vertebra (20.4 mm). The analysis indicates that the stress on the lower surface of the vertebral body in thoracolumbar scoliosis tended to be locally concentrated, especially on the concave side of the primary curvature's vertebral body (the maximum stress on the lower surface of T9 is 32.33 MPa) and the convex side of the compensatory curvature's vertebral body (the maximum stress on the lower surface of L5 is 41.97 MPa).

CONCLUSION

This study provides a high-precision modeling and analysis method for scoliosis with full consideration of gravity. The reliability of the method was verified based on patient data. This model can be used to analyze the biomechanical characteristics of patients in the treatment plan design stage.

Urotensin II-related peptides, Urp1 and Urp2, control zebrafish spine morphology

The spine provides structure and support to the body, yet how it develops its characteristic morphology as the organism grows is little understood. This is underscored by the commonality of conditions in which the spine curves abnormally such as scoliosis, kyphosis, and lordosis. Understanding the origin of these spinal curves has been challenging in part due to the lack of appropriate animal models. Recently, zebrafish have emerged as promising tools with which to understand the origin of spinal curves. Using zebrafish, we demonstrate that the urotensin II-related peptides (URPs), Urp1 and Urp2, are essential for maintaining spine morphology. Urp1 and Urp2 are 10-amino acid cyclic peptides expressed by neurons lining the central canal of the spinal cord. Upon combined genetic loss of Urp1 and Urp2, adolescent-onset planar curves manifested in the caudal region of the spine. Highly similar curves were caused by mutation of Uts2r3, an URP receptor. Quantitative comparisons revealed that urotensin-associated curves were distinct from other zebrafish spinal curve mutants in curve position and direction. Last, we found that the Reissner fiber, a proteinaceous thread that sits in the central canal and has been implicated in the control of spine morphology, breaks down prior to curve formation in mutants with perturbed cilia motility but was unaffected by loss of Uts2r3. This suggests a Reissner fiber-independent mechanism of curvature in urotensin-deficient mutants. Overall, our results show that Urp1 and Urp2 control zebrafish spine morphology and establish new animal models of spine deformity.

Correlational analysis of three-dimensional spinopelvic parameters with standing balance and gait characteristics in adolescent idiopathic scoliosis: A preliminary research on Lenke V

Background: Adolescent idiopathic scoliosis (AIS), the most common spinal deformity, possibly develops due to imbalanced spinal loading following asymmetric development. Since altered loading patterns may affect standing balance and gait, we investigated whether a correlation exists between balance ability, gait pattern, and the three-dimensional radiographic spinopelvic parameters in AIS patients. Methods: A cross-sectional observational study was conducted with 34 AIS patients (aged 10-18 years) and an equal number of healthy age and sex-matched teenagers (normal group). We obtained the spinopelvic three-dimensional parameters and balance parameters simultaneously through the EOS imaging system and gait and center of pressure (CoP) characteristics using a plantar pressure measurement mat. Besides determining the intergroup differences in balance and gait parameters, multiple linear regression analyses were performed to identify any correlation between the static plantar pressure and radiographic parameters. Results: Compared to the normal group, the CoPx is lower, the CoP path length and 90% confidence ellipse area were significantly higher in AIS patients (AIS: -13.7 ± 5.7 mm, 147.4 ± 58.1 mm, 150.5 ± 62.8 mm2; normal: -7.0 ± 5.4 mm, 78.8 ± 32.0 mm, 92.1 ± 41.7 mm2, respectively), correlated with apical vertebra translation, sagittal pelvic tilt, and pelvis axial rotation, respectively. Moreover, AIS patients had a shorter stance phase (61.35 ± 0.97 s vs. 62.39 ± 1.09 s), a longer swing phase (38.66 ± 0.97 s vs. 37.62 ± 1.08 s), and smaller maximum pressure peaks in the gait cycle, especially on the left foot, as compared to healthy subjects. Moreover, the CoP trajectory in AIS patients was different from the latter, and changes in the bipedal trend were not consistent. Conclusion: The standing balance and gait characteristics of AIS patients are different from those of healthy subjects, as reflected in their three-dimensional spinopelvic radiographic parameters. Trial registration: The study protocol was registered with the Chinese Clinical Trial Registry (Number ChCTR1800018310) and the Human Subject Committee of Guangzhou Sport University (Number: 2018LCLL003).

The preliminary outcomes of vertebral body tethering in treating adolescent idiopathic scoliosis: a systematic review

PURPOSE

VBT is a novel alternative to spinal fusion surgery to treat skeletally immature AIS and was approved to correct idiopathic scoliosis in August 2019 by US Federal Drug Administration (FDA). To systemically review the preliminary outcomes of vertebral body tethering (VBT) in treating adolescent idiopathic scoliosis.

METHODS

The electronic databases PubMed, EMBASE, and Web of Science were queried up to January 2022 for articles regarding VBT. Basic characteristics of patients, changes of radiographic parameters in coronal and sagittal planes, and clinical outcomes of surgical treatment of VBT including complication and revision rates were summarized.

RESULTS

Twenty five studies met the inclusion criteria. Most studies (23/25) included patients with only skeletal immaturity. The average % correction of the main/tethered curve at final follow-up, and % correction of thoracic kyphosis at final follow-up were reported to be 15.6-106.5% and - 31.8 to 20.0%, respectively. The most common complications for VBT were tether breakage (n = 145;21.3%), pulmonary complications (n = 49; 6.9%), and overcorrection (n = 30; 4.2%). The revision rate was 13.1%.

CONCLUSION

VBT could effectively and safely correct spinal deformity in skeletally immature patients with AIS and preserve the motion and growth of the spine. However, VBT has a relatively high complication and revision rates. Therefore, surgeons should cautiously consider VBT for treating AIS. Future research efforts are needed to lower the complication and revision rates. Whatever, VBT is still in its infancy and may have a promising future as a non-fusion solution for AIS.

Reliability of a three-dimensional spinal proprioception assessment for patients with adolescent idiopathic scoliosis

PURPOSE

Although it is evident that some patients with adolescent idiopathic scoliosis (AIS) have proprioceptive deficit in peripheral joints, knowledge on the proprioceptive function of the deformed spine is limited. Nonetheless, spinal proprioception in AIS may be affected three-dimensionally, prior studies only focussed on evaluating peripheral proprioception in single plane. Therefore, this study aimed to develop a novel spinal proprioception assessment using three-dimensional motion analysis in patients with AIS.

METHODS

Participants were included if they had a primary diagnosis of AIS who did not receive or failed conservative treatments. Three trunk repositioning tests involving flexion-extension, lateral-flexion, and axial-rotation were conducted. A three-dimensional kinematics of the trunk was used as the outcome measures. The proprioceptive acuity was quantified by the repositioning error. The intra-examiner and test-retest reliability were analysed by the intraclass correlation coefficient (ICC).

RESULTS

Fifty-nine patients with AIS were recruited. Regarding the trunk flexion-extension test, the single measure ICC showed moderate reliability (0.46) and the average measures ICC demonstrated good reliability (0.72). As for the trunk lateral-flexion test, the reliability of single measure and average measures ICC was moderate (0.44) and good (0.70) reliability, respectively. For the trunk axial-rotation test, the single measure ICC indicated fair reliability (0.32), while the average measures ICC showed moderate reliability (0.59).

CONCLUSION

This is the first study to evaluate the reliability of novel three-dimensional spinal proprioception assessments in patients with AIS. The trunk flexion-extension repositioning test may be preferable clinical test given its highest reliability.

Evaluating bone quality and asymmetrical aplasia of the thoracic vertebral body in Lenke 1A adolescent idiopathic scoliosis using hounsfield units

Study Design

Retrospective analysis.

Objective

To evaluate bone quality and investigate asymmetrical development of the thoracic vertebral body in adolescent idiopathic scoliosis (AIS) based on Hounsfield unit (HU) measurements obtained from computed-tomography (CT) scans.

Summary of Background Data

HU value demonstrated higher reliability and accuracy than the traditional method, indicating that they could be used to individually evaluate and effectively assess the bone quality of every vertebra in the CT films.

Methods

Total 30 AIS patients classified as Lenke Type 1A and 30 paired controls were included in this study. Regions of interest for HU value were measured on three horizontal images of the thoracic vertebrae. HU measurements of the whole vertebral body in each vertebra were obtained. Using HU value, we separately measured the concave and convex sides of each vertebral body in patients' group, as well as within the left and right sides in controls.

Results

In controls, the mean HU value of T1–T12 thoracic vertebral bodies was 240.03 ± 39.77, with no statistical differences among different levels. As for AIS patients, in the structural curve, the apical region had a significantly lower HU compared with the other regions, and asymmetrical change was found between the concave and convex sides, most significantly in the apical region. In the non-structural curve, the average HU value was 254.99 ± 44.48, and no significant difference was found either among the different levels of vertebrae or between the concave and convex sides.

Conclusions

Abnormal and asymmetrical changes in bone quality of the thoracic vertebral body in patients with Lenke 1A AIS were indicated. Low bone quality in the convex side of the structural curve indicated stronger internal fixation in surgery to correct the deformity.

The Impact of Training Time on Understanding the Treatment of Adolescent Idiopathic Scoliosis According to SOSORT International Guidelines: An Online Survey Study

The lack of knowledge by health professionals in the management of scoliosis can lead to an erroneous diagnosis. The aim of the current study was to understand the influence of length of professional experience on the knowledge of Brazilian physical therapists regarding international guidelines for the treatment of adolescent idiopathic scoliosis. The study was conducted using an online questionnaire consisting of 23 questions, divided into 8 questions on sociodemographic data and 15 questions based on information provided by the guidelines in the SOSORT 2016. In total, 506 physiotherapists were interviewed, and they comprised the study sample. The results showed that professionals who have been working for more than 6 years in the field have greater knowledge of AIS, seek to become more professional, and with that, have an understanding of AIS that is more aligned with the SOSORT. Length of experience made a difference when considering knowledge of the treatment of idiopathic scoliosis. The present study showed that a time since graduation of 6 years or more was satisfactory.

Timely Revisit of Proprioceptive Deficits in Adolescent Idiopathic Scoliosis: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVES

The present review aimed to summarize the evidence regarding differences in proprioception between children with and without adolescent idiopathic scoliosis (AIS).

METHODS

Seven electronic databases were searched from their inception to April 10, 2021. Articles were included if they involved: (1) AIS patients aged between 10 and 18 years, (2) measurements of proprioceptive abilities, and (3) comparisons with non-AIS controls. Animal studies, case reports, commentaries, conference proceedings, research protocols, and reviews were excluded. Two reviewers independently conducted literature screening, data extraction, risks of bias assessments, and quality of evidence evaluations. Relevant information was pooled for meta-analyses.

RESULTS

From 432 identified citations, 11 case-control studies comprising 1121 participants were included. The meta-analyses showed that AIS participants displayed proprioceptive deficits as compared to non-AIS controls. Moderate evidence supported that AIS participants showed significantly larger repositioning errors than healthy controls (pooled mean difference = 1.27 degrees, P < .01). Low evidence substantiated that AIS participants had significantly greater motion detection threshold (pooled mean difference = 1.60 degrees, P < .01) and abnormal somatosensory evoked potentials (pooled mean difference = .36 milliseconds, P = .01) than non-AIS counterparts.

CONCLUSIONS

Consistent findings revealed that proprioceptive deficits occurred in AIS patients. Further investigations on the causal relationship between AIS and proprioception, and the identification of the subgroup of AIS patients with proprioceptive deficit are needed.

Additive Manufacturing of Spinal Braces: Evaluation of Production Process and Postural Stability in Patients with Scoliosis

Spinal orthoses produced using additive manufacturing show great potential for obtaining patient-specific solutions in clinical applications, reducing manual operations, time consumption, and material waste. This study was conducted to evaluate the production process of spinal orthoses produced by additive manufacturing, and to test the effects of 3D-printed braces on postural stability in patients with adolescent idiopathic scoliosis and osteogenesis imperfecta. Ten patients were recruited consecutively and were asked to wear a spinal orthosis produced by additive manufacturing for 2 weeks. The four phases of the production process for each brace were evaluated separately on a scale from 0 (not acceptable) to 3 (optimal). Postural stability in the unbraced and the two braced conditions (3D-printed and conventional) was assessed using validated metrics obtained from a wearable inertial sensor. The production process was evaluated as good in four cases, acceptable in five cases, and not acceptable in one case, due to problems in the printing phase. No statistically significant differences were observed in any of the postural balance metrics between the 3D-printed and conventional brace. On the other hand, postural balance metrics improved significantly with both types of braces with respect to the unbraced condition. Spinal orthoses produced with an innovative production process based on digital scans, CAD, and 3D printing are valid alternatives to conventionally produced orthoses, providing equivalent postural stability.

Zebrafish: an important model for understanding scoliosis

Scoliosis is a common spinal deformity that considerably affects the physical and psychological health of patients. Studies have shown that genetic factors play an important role in scoliosis. However, its etiopathogenesis remain unclear, partially because of the genetic heterogeneity of scoliosis and the lack of appropriate model systems. Recently, the development of efficient gene editing methods and high-throughput sequencing technology has made it possible to explore the underlying pathological mechanisms of scoliosis. Owing to their susceptibility for developing scoliosis and high genetic homology with human, zebrafish are increasingly being used as a model for scoliosis in developmental biology, genetics, and clinical medicine. Here, we summarize the recent advances in scoliosis research on zebrafish and discuss the prospects of using zebrafish as a scoliosis model.

Investigation of ultrasonic soft tissue-bone reflection coefficients correlating with curve severity in children with adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is a three-dimensional curvature of spine. Children with AIS and low bone quality have higher chance to get curve progression leading to bigger spinal curvature. In addition, bone quality affects acoustic impedance of bone, thus influencing the reflection coefficient of ultrasound signal from the soft tissue–bone interface. This study aimed to estimate the bone quality of AIS patients based on the reflection coefficients to determine the correlation of the bone quality with curve severity. A simple bone model was used to develop an equation to calculate the reflection coefficient value. Experiments were conducted on five different phantoms. Acrylic was used to design a vertebral shape to study the effect of surface roughness and inclination, including: smooth flat surface (SFS), smooth curved surface (SCS), rough curved surface (RCS), and the rough curved inclined surface (RCIS). A clinical study with 37 AIS patients were recruited. The estimated reflection coefficient values of plate phantoms agreed well with the predicted values and the maximum error was 6.7%. The reflection coefficients measured from the acrylic-water interface for the SFS, SCS, RCS, RCIS (3° and 5°) were 0.37, 0.33, 0.28, (0.23 and 0.12), respectively. The surface roughness and inclination increased the reflection loss. From the clinical data, the average reflection coefficients for children with AIS were 0.11 and 0.07 for the mild curve group and the moderate curve group, respectively. A moderate linear correlation was found between the reflection coefficients and curve severity (r2 = 0.3). Patients with lower bone quality have observed to have larger spinal curvature.

The association between idiopathic scoliosis and growth hormone treatment in short children

PURPOSE

Idiopathic scoliosis is the most common form of scoliosis, and the risk of onset and progression has been found to correlate with growth spurts. Therefore, treatment with recombinant human growth hormone (GH) treatment in short children may initiate and/or aggravate scoliosis. The aim of this study was to investigate the relationship between idiopathic scoliosis and GH treatment in short children.

METHODS

The medical records of 113 subjects seen at the participating institution between January 2010 and December 2020 and who were diagnosed with GH deficiency and small for gestational age, had idiopathic short stature, and were treated with GH for at least one year were reviewed. Scoliosis was defined as a Cobb angle greater than 10 degrees as assessed using a spine x-ray. Clinical data and laboratory findings before and 12 months after GH treatment were compared.

RESULTS

There was significant increase in height, height-standard deviation score, insulin-like growth factor 1, and insulin-like growth factor binding protein 3 (p<0.001) with GH treatment. However, there were no significant differences in the average Cobb angle (6.2°±3.3° vs. 6.1°±3.5°, p=0.842) and the prevalence of scoliosis (9.7% vs. 13.3%, p=0.481) before and after one year of GH treatment. A comparative analysis of both initial Cobb angle and change in Cobb angle during GH treatment showed no relationship with other factors.

CONCLUSION

Although GH treatment in short children increased height and growth velocity, it was not associated with development or aggravation of idiopathic scoliosis.

Biological effect of dysregulated LBX1 on adolescent idiopathic scoliosis through modulating muscle carbohydrate metabolism

BACKGROUND CONTEXT

Abnormal energy metabolism such as lower body weight and body mass index (BMI) and less fat mass is widely reported in patients with adolescent idiopathic scoliosis (AIS) and has been implicated in deformity development. However, the underlying mechanism is largely unclear. LBX1 is one of the promising AIS predisposing genes validated by multicenter studies.

PURPOSE

This study aimed to identify differentially expressed proteins (DEPs) relating to energy metabolism in AIS by using proteomic and metabolic analysis and to explore if the expression of these DEPs is associated with clinical parameters and modulated by LBX1.

STUDY DESIGN

This is a cross-sectional study using clinical data and biological samples followed by basic study using a cellular model.

PATIENT SAMPLE

Plasma samples were collected from Chinese girls with nonprogressive and progressive AIS (N=7 and 8, respectively) and age-matched healthy girls (N=50). Paraspinal muscle tissues were collected intraoperatively from concave and convex side of the apex of the major spinal curve in AIS (N=24) and either side from nonscoliosis patients (N=14).

OUTCOME MEASURES

Radiological Cobb angle and basic anthropometric data of recruited subjects were measured. The DEPs and metabolites were compared in plasma using proteomics and metabolomics technique. The relative expression of selected genes was measured in muscles.

METHODS

Plasma samples from AIS were collected at first clinical visit and were further divided into nonprogressive or progressive groups according to Cobb angle changes in 6-year follow-up. Age-matched healthy girls were recruited as control. High-performance liquid chromatography-mass spectrometry based proteomic analysis was carried out in three groups to identify DEPs and their annotated metabolic pathways. An independent cohort was used for validation by gas chromatography-mass spectrometry based metabolomic analysis. Paraspinal muscles were subjected to quantitative polymerase chain reaction (qPCR) followed by correlation analysis. Human skeletal muscle myoblast (HSMM) was used as the cellular model.

RESULTS

The likelihood of aberrant galactose metabolism and glycolysis was found to be associated with AIS curve progression as evidenced by the thirteen DEPs and seven related metabolites according to proteomic and metabolomic analysis. Some of the DEPs showed significantly altered expression in AIS concave and convex sides paraspinal muscles compared with those in nonscoliosis control. Four DEPs were found significantly and negatively correlated with LBX1 in AIS convex side paraspinal muscles. Overexpressing LBX1 in HSMM cells led to increased expression of three DEPs and decreased expression of three DEPs, respectively.

CONCLUSIONS

This is the first integrated proteomic and metabolomic analysis on AIS. Our findings show dysregulated galactose metabolism and glycolysis pathways in progressive group of AIS, suggesting the presence of abnormal energy metabolism at early stage of this disease, and their association with higher risk of progressing into more severe curvature. Evidence from ex vivo study with human muscle biopsies and in vitro study with human myoblast cells propose the possible effect of LBX1 on these two pathways in skeletal muscles. The present study provides new evidence of LBX1 function in AIS via modulating effect on the expression of energy metabolism related genes. This study might provide new insights into etiopathogenesis and development of novel treatment strategy targeting on abnormal body weight and BMI in patients with AIS. Additionally, the plasma proteomic and metabolomic studies suggested new candidates as biomarkers for establishing predictive model for AIS onset/progression.

Reliability, Quality, and Educational Suitability of TikTok Videos as a Source of Information about Scoliosis Exercises: A Cross-Sectional Study

This study aimed to systematically assess the informational reliability, quality, and educational suitability of videos introducing scoliosis exercises on TikTok. We retrieved and screened 1904 TikTok videos with the hashtags: “#scoliosis”, “#scoliosisexercise”, and “#scoliosistips”, before collecting a final sample of 171 scoliosis exercises in March 2022. Then, two independent raters assessed the reliability and quality of the videos using the DISCERN instrument and evaluated the educational suitability of the information using “Scoliosis Exercise Education Score” (SEES; exercise cycle, target, effect, precaution, and rationale). None of the videos were rated as excellent or good according to DISCERN. The mean SEES score was 2.02 out of 5. Videos uploaded by health organizations had significantly lower DISCERN and SEES scores than those by general users and healthcare professionals. Regarding the propriety of physiotherapeutic scoliosis-specific exercises (PSSE), DISCERN and SEES scores were significantly higher in the PSSE proper group than in the PSSE non-proper group. Although TikTok has become a popular source of scoliosis-related information, the overall information quality, reliability, and educational suitability of videos on scoliosis exercises in TikTok appear to be low, suggesting that TikTok is not suitable source for obtaining scoliosis exercise information.

Conformity assessment of a computer vision-based posture analysis system for the screening of postural deformation

Background

This study evaluates the conformity of using a computer vision-based posture analysis system as a screening assessment for postural deformity detection in the spine that is easily applicable to clinical practice.

Methods

One hundred forty participants were enrolled for screening of the postural deformation. Factors that determine the presence or absence of spinal deformation, such as shoulder height difference (SHD), pelvic height difference (PHD), and leg length mismatch (LLD), were used as parameters for the clinical decision support system (CDSS) using a commercial computer vision-based posture analysis system. For conformity analysis, the probability of postural deformation provided by CDSS, the Cobb angle, the PHD, and the SHD was compared and analyzed between the system and radiographic parameters. A principal component analysis (PCA) of the CDSS and correlation analysis were conducted.

Results

The Cobb angles of the 140 participants ranged from 0° to 61°, with an average of 6.16° ± 8.50°. The postural deformation of CDSS showed 94% conformity correlated with radiographic assessment. The conformity assessment results were more accurate in the participants of postural deformation with normal (0–9°) and mild (10–25°) ranges of scoliosis. The referenced SHD and the SHD of the CDSS showed statistical significance (p < 0.001) on a paired t-test. SHD and PHD for PCA were the predominant factors (PC1 SHD for 79.97%, PC2 PHD for 19.86%).

Conclusion

The CDSS showed 94% conformity for the screening of postural spinal deformity. The main factors determining diagnostic suitability were two main variables: SHD and PHD. In conclusion, a computer vision-based posture analysis system can be utilized as a safe, efficient, and convenient CDSS for early diagnosis of spinal posture deformation, including scoliosis.

The Adolescent Spine

Adolescent idiopathic scoliosis (AIS) is the most characteristic disorder of the adolescent spine. It is a three-dimensional (3D) disorder that occurs from 10 years of age and comprises 90% of all idiopathic scolioses. Imaging plays a central role in the diagnosis and follow-up of patients with AIS. Modern imaging offers 3D assessment of scoliosis with less radiation exposure. Imaging helps rule out occult conditions that cause spinal deformity. Various imaging methods are also used to assess skeletal maturity in patients with AIS, thus determining the growth spurt and risk of progression of scoliosis. This article provides a brief overview of the pathophysiology, biomechanics, clinical features, and modern imaging of AIS relevant to radiologists in clinical settings.

Identification of FAT3 as a new candidate gene for adolescent idiopathic scoliosis

In an effort to identify rare alleles associated with adolescent idiopathic scoliosis (AIS) whole-exome sequencing was performed on a discovery cohort of 73 unrelated patients and 70 age-and sex matched controls, all of French-Canadian ancestry. A collapsing gene burden test was performed to analyze rare protein-altering variants using case–control statistics. Since no single gene achieved statistical significance, targeted exon sequencing was performed for 24 genes with the smallest p values, in an independent replication cohort of unrelated severely affected females with AIS and sex-matched controls (N = 96 each). An excess of rare, potentially protein-altering variants was noted in one particular gene, FAT3, although it did not achieve statistical significance. Independently, we sequenced the exomes of all members of a rare multiplex family of three affected sisters and unaffected parents. All three sisters were compound heterozygous for two rare protein-altering variants in FAT3. The parents were single heterozygotes for each variant. The two variants in the family were also present in our discovery cohort. A second validation step was done, using another independent replication cohort of 258 unrelated AIS patients having reach their skeletal maturity and 143 healthy controls to genotype nine FAT3 gene variants, including the two variants previously identified in the multiplex family: p.L517S (rs139595720) and p.L4544F (rs187159256). Interestingly, two FAT3 variants, rs139595720 (genotype A/G) and rs80293525 (genotype C/T), were enriched in severe scoliosis cases (4.5% and 2.7% respectively) compared to milder cases (1.4% and 0.7%) and healthy controls (1.6% and 0.8%). Our results implicate FAT3 as a new candidate gene in the etiology of AIS.

Systematic review of the association between isolated musculoskeletal hypermobility and adolescent idiopathic scoliosis

INTRODUCTION

Adolescent idiopathic scoliosis (AIS) affects 1-3% of the population, but its pathogenesis remains unclear. The coexistence of musculoskeletal hypermobility and scoliosis in many inherited syndromes raises the possibility that isolated musculoskeletal hypermobility may contribute to AIS development or progression.

METHODS

We performed a systematic review of the evidence for a relationship between isolated musculoskeletal hypermobility and AIS. A meta-analysis was planned, but if not possible, a narrative evidence synthesis was planned.

RESULTS

Nineteen studies met eligibility criteria for inclusion. One study was excluded due to insufficient quality. Substantial heterogeneity in study design and methodology negated meta-analysis, so a narrative review was performed. Of the 18 studies included, seven suggested a positive association and eight found no association. Three reported the prevalence of musculoskeletal hypermobility in individuals with AIS. Overall, there was no convincing population-based evidence for an association between musculoskeletal hypermobility and AIS, with only two case-control studies by the same authors presenting compelling evidence for an association. Although populations at extremes of hypermobility had a high prevalence of spinal curvature, these studies were at high risk of confounding. Wide variation in methods of measuring musculoskeletal hypermobility and the challenge of assessing AIS in population-based studies hinder study comparison.

CONCLUSIONS

There is a paucity of high-quality evidence examining the association between isolated musculoskeletal hypermobility and AIS. Large-scale prospective studies with adequate adjustment for potential confounding factors could clarify the relationship between musculoskeletal hypermobility and AIS to elucidate its role in the pathogenesis of AIS.

Case Report: DNAAF4 Variants Cause Primary Ciliary Dyskinesia and Infertility in Two Han Chinese Families

Background: Primary ciliary dyskinesia (PCD) is a rare genetic disorder, predominantly autosomal recessive. The dynein axonemal assembly factor 4 (DNAAF4) is mainly involved in the preassembly of multisubunit dynein protein, which is fundamental to the proper functioning of cilia and flagella. There are few reports of PCD-related pathogenic variants of DNAAF4, and almost no DNAAF4-related articles focused on sperm phenotype. Moreover, the association between DNAAF4 and scoliosis has never been reported, to the best of our knowledge.

Materials and Methods: We recruited two patients with a clinical diagnosis of PCD. One came from a consanguineous and another from a non-consanguineous family. Clinical data, laboratory test results, and imaging data were analyzed. Through whole exome sequencing, immunofluorescence, electron microscopy, high-speed video microscopy analysis, and hematoxylin–eosin (HE) staining, we identified the disease-associated variants and validated the pathogenicity.

Results: Proband 1 (P1, F1: II-1), a 19-year-old man, comes from a non-consanguineous family-I, and proband 2 (P2, F2: II-1), a 37-year-old woman, comes from a consanguineous family-II. Both had sinusitis, bronchiectasis, situs inversus, and scoliosis. P1 also had asthenoteratozoospermia, and P2 had an immature uterus. Two homozygous pathogenic variants in DNAAF4 (NM_130810.4), c.988C &gt; T, p.(Arg330Trp), and DNAAF4 (NM_130810.4), c.733 C &gt; T, p.(Arg245*), were identified through whole exome sequencing. High-speed microscopy analysis showed that most of the cilia were static in P1, with complete static of the respiratory cilia in P2. Immunofluorescence showed that the outer dynein arms (ODA) and inner dynein arms (IDA) were absent in the respiratory cilia of both probands, as well as in the sperm flagellum of P1. Transmission electron microscopy revealed the absence of ODA and IDA of respiratory cilia of P2, and HE staining showed irregular, short, absent, coiled, and bent flagella.

Conclusion: Our study identified a novel variant c.733C &gt; T, which expanded the spectrum of DNAAF4 variants. Furthermore, we linked DNAAF4 to asthenoteratozoospermia and likely scoliosis in patients with PCD. This study will contribute to a better understanding of PCD.

Morphological changes of Intervertebral Disc detectable by T2-weighted MRI and its correlation with curve severity in Adolescent Idiopathic Scoliosis

Background

Our previous studies found disproportionate anteroposterior vertebral size is associated with severity of the scoliotic curves in adolescent idiopathic scoliosis (AIS) patients. Subsequent studies showed wedging of vertebral bodies (VB) had less contribution than intervertebral discs (IVD) to the anterior–posterior vertebral column length discrepancy in severe-AIS. However, the exact morphological changes of IVD were not clearly defined. This study aimed to evaluate the morphological and pathological changes of IVD and VB in AIS girls and healthy female controls.

Methods

This study included 33 age-matched female controls and 76 AIS girls with a right-sided thoracic curvature. Wedge angle, height ratio and distance ratio of VB and IVD were measured on the best midline coronal and sagittal planes from reformatted MRI spine. Volumes of VB, IVD and nucleus pulposus (NP) were also evaluated on volumetric images. One-way ANOVA with Bonferroni correction and Pearson correlation tests were used.

Results

There was significant difference in wedge angle and height ratio of VB and IVD between AIS and controls. In severe-AIS, the position of NP was significantly shifted to the convexity when compared with non-severe AIS and controls. Whereas, the volume of IVD and NP in severe-AIS was found to be significantly smaller. In addition, Cobb angle was significantly correlated with wedge angle and height ratio, and inversely correlated with the volume of NP.

Conclusions

In addition to wedging of VB and IVD, there was significantly reduced volume of IVD and NP in AIS patients with severe curve, insinuating the mechanical effect of scoliosis leads to a compression on both IVD and NP before significant disc desiccation occurs. We postulate that the compression of IVD and NP can contribute to curve progression in severe-AIS, these patients are more prone to disc degeneration in adulthood if no operative treatment is offered. Further longitudinal study on these parameters is still warranted.

Asymmetrical thoracic-lumbar coordination during trunk rotation between adolescents with and without thoracic idiopathic scoliosis

STUDY DESIGN

Cross-sectional comparative study.

PURPOSE

To compare thoracic-lumbar kinematic changes and coordination based on coupling angles (CAs) in two different directions of trunk rotation between adolescents with idiopathic scoliosis (AIS) and control subjects. Altered three-dimensional (3D) deviations are often apparent in AIS groups during functional activities, such as gait. However, there is a lack of consistent evidence on coordinated motions during different directions of trunk rotation.

METHODS

This study included 14 AIS and 17 age-matched control subjects who were all right limb dominant. A motion capture system was utilized to analyze the spinal segment motions. The outcome measures included range of motion (ROM) at the first thoracic (T1), seventh thoracic (T7), and first lumbar (L1) spinous processes as well as the sacral tubercle (S1). The CAs compared in-phase (rotation from right to left) and anti-phase (rotation from left to right) trunk rotations.

RESULTS

Although there was no significant association with the spinal segments in the control group, the Cobb angle demonstrated significant positive correlations with anti-phase at T7 and L1 as well as in-phase at L1. Regarding the CAs, the groups demonstrated a significant interaction with both phases (F = 4.7, p = 0.04). The AIS group demonstrated positive correlations with ROM during in-phase at L1 and anti-phase at T7 and L1.

CONCLUSION

The coordination based on the CAs of the lumbar spine relative to the thoracic spine significantly decreased during left to right trunk rotation in the AIS group. These results indicated that the AIS group demonstrated directional dissociation toward the dominant side of lumbar rotation.

LEVEL OF EVIDENCE

III.

Upregulation of microRNA-96-5p is associated with adolescent idiopathic scoliosis and low bone mass phenotype

Bone densitometry revealed low bone mass in patients with adolescent idiopathic scoliosis (AIS) and its prognostic potential to predict curve progression. Recent studies showed differential circulating miRNAs in AIS but their diagnostic potential and links to low bone mass have not been well-documented. The present study aimed to compare miRNA profiles in bone tissues collected from AIS and non-scoliotic subjects, and to explore if the selected miRNA candidates could be useful diagnostic biomarkers for AIS. Microarray analysis identified miR-96-5p being the most upregulated among the candidates. miR-96-5p level was measured in plasma samples from 100 AIS and 52 healthy girls. Our results showed significantly higher plasma levels of miR-96-5p in AIS girls with an area under the curve (AUC) of 0.671 for diagnostic accuracy. A model that was composed of plasma miR-96-5p and patient-specific parameters (age, body weight and years since menarche) gave rise to an improved AUC of 0.752. Ingenuity Pathway Analysis (IPA) indicated functional links between bone metabolic pathways and miR-96-5p. In conclusion, differentially expressed miRNAs in AIS bone and plasma samples represented a new source of disease biomarkers and players in AIS etiopathogenesis, which required further validation study involving AIS patients of both genders with long-term follow-up.

Genetic variants associated with the occurrence and progression of adolescent idiopathic scoliosis: a systematic review protocol

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is a structural lateral spinal curvature of ≥ 10° with rotation. Approximately 2-3% of children in most populations are affected with AIS, and this condition is responsible for approximately $1.1 billion in surgical costs to the US healthcare system. Although a genetic factor for AIS has been demonstrated for decades, with multiple potentially contributory loci identified across populations, treatment options have remained limited to bracing and surgery.

METHODS

The databases MEDLINE (via PubMed), Embase, Google Scholar, and Ovid MEDLINE will be searched and limited to articles in English. We will conduct title and abstract, full-text, and data extraction screening through Covidence, followed by data transfer to a custom REDCap database. Quality assessment will be confirmed by multiple reviewers. Studies containing variant-level data (i.e., GWAS, exome sequencing) for AIS subjects and controls will be considered. Outcomes of interest will include presence/absence of AIS, scoliosis curve severity, scoliosis curve progression, and presence/absence of nucleotide-level variants. Analyses will include odds ratios and relative risk assessments, and subgroup analysis (i.e., males vs. females, age groups) may be applied. Quality assessment tools will include GRADE and Q-Genie for genetic studies.

DISCUSSION

In this systematic review, we seek to evaluate the quality of genetic evidence for AIS to better inform research efforts, to ultimately improve the quality of patient care and diagnosis.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration #CRD42021243253.

Assessment of changes in the sagittal plane of the spine in girls with adolescent idiopathic scoliosis using the moire method

BACKGROUND

The gold standard in the clinical assessment of the extent of scoliosis is the Cobb method but the analysis also covers the changes that occur within the spine and trunk in relation to the transverse and sagittal planes.

OBJECTIVE

The study aimed to estimate changes in the sagittal plane of the spine in girls with right-sided thoracic adolescent idiopathic scoliosis.

METHODS

The study involved 29 girls with scoliosis (13.6 ± 0.6 years) and 36 healthy girls as the comparison group. The tests included an interview, clinical examination (with the use of Adam's test and the Cobb angle), and examination of shape of the spine surface with the use of the photogrammetric method and the projection moire effect.

RESULTS

Lower values of the thoracic kyphosis parameters were found in the scoliosis group. Significant differences were noted for the parameters of the lumbosacral section α (p= 0.02), thoracolumbar section β (p< 0.001), the upper thoracic section γ (p< 0.001), thoracolumbar and upper thoracic section β+γ (p< 0.001) and the total size of α+β+γ (p< 0.001) curvatures.

CONCLUSIONS

The study showed that with an increase in the angular value of the thoracic curvature, the thoracic kyphosis decreased.

Ethnic Disparity in the Incidence of Scoliosis Among Adolescents in Tianzhu Tibetan Autonomous County, China

Objectives

To determine the influence of ethnic disparities, socioeconomic status (SES) and hukou on the incidence of scoliosis.

Methods

We enrolled 2,445 junior high school students (Han: 1,153; ethnic minorities: 1,292) aged 12–16 years from two schools in Tianzhu Tibetan Autonomous County, Gansu Province from November 2020 to February 2021. We measured the angle of trunk rotation (ATR) using a scoliometer. Two-factor analysis of variance was used to comparatively analyze differences in the ATR according to ethnicity, age, sex, body mass index (BMI), and SES between the groups. Associations between risk factors and scoliosis were estimated using odds ratios and 95% confidence intervals with an unconditional multivariate logistic regression model for the two groups.

Results

Adolescents with Han ethnicity were more likely to have scoliosis than their ethnic minority counterparts (10.8% vs. 7.1%, P < 0.05). The ATR value in the Han group decreased with age whereas the minority group showed an upward trend (P < 0.05). The difference between ethnic groups was not significant, only at level 3. In particular, the ATR values among Han girls were significantly higher than those of ethnic minority girls (P < 0.05). Compared with Han adolescents, the BMI of ethnic minorities had a greater impact on the ATR. A statistically significant difference in SES was found between the two ethnic groups (P < 0.05). Hukou and parents' occupation had an important influence on the onset of scoliosis.

Conclusions

Han adolescents had higher ATR values and were more likely to have scoliosis than ethnic minority adolescents in our study. Growth and development indicators (height and BMI) and differences in SES between the two groups played an important role.

Assessing Bone Quality of the Spine in Children with Scoliosis Using the Ultrasound Reflection Frequency Amplitude Index Method: A Preliminary Study

Osteopenia is considered a common phenomenon in patients who have scoliosis. Quantitative ultrasound has been used to assess skeletal status for decades, and recently ultrasound imaging using reflection signals from vertebrae were as well applied to measure spinal curvatures in children with scoliosis. The objectives of this study were to develop a new method that can robustly extract a parameter from ultrasound spinal data for estimating bone quality of scoliotic patients and to investigate the potential of the parameter in predicting curve progression. The frequency amplitude index (FAI) was calculated based on the spectrum of the original radiofrequency signals reflected from the tissue-vertebra interface. The correlation between FAI and reflection coefficient was validated using decalcified bovine bone samples in vitro, and the FAIs of scoliotic subjects were investigated in vivo with reference to body mass index, Cobb angles and curve progression status. The results revealed that the intra-rater measures were highly reliable between different trials (intra-class correlation coefficient = 0.997). The FAI value was strongly correlated with the reflection coefficient of bone tissue (R² = 0.824), and the lower FAI indicated the higher risk of curve progression for the non-mild scoliosis cases. This preliminary study found that the FAI method can provide a feasible and robust approach to assessment of the bone quality of spine and may be a promising factor in monitoring curve progression of patients who have adolescent idiopathic scoliosis.

Exploration of Contributory Factors to an Unpleasant Bracing Experience of Adolescent Idiopathic Scoliosis Patients a Quantitative and Qualitative Research

BACKGROUND

To obtain a better understanding of the wearing habits and preferences of Adolescent Idiopathic Scoliosis (AIS) patients undergoing rigid brace treatment, we examine what factors contribute to patients' perceived discomfort during the treatment.

METHODS

Seventeen AIS patients treated with a rigid brace were recruited. We asked them to complete a questionnaire and participate in an interview study. Finally, we measure the interface corrective force and perceived discomfort with the participants for different positions and assess the correlation.

RESULTS

Our survey reveals that participants scored the lowest in the domains of environmental factors, psycho-spiritual factors, satisfaction, and self-image. Appearance anxiety, physical and psychological discomfort and inconvenience were the three most frequently mentioned problems in the interviews on participants' daily bracing experiences. A significant, moderately positive relationship between corrective force and discomfort level was found only when participants were lying on their left side, but not in any of the other positions. No significant correlation between treatment length and perceived discomfort was found.

CONCLUSIONS

Future work should focus on reducing the psychological burden and the inconvenience of wearing a brace, rather than on reducing physical discomfort resulting from the corrective force.

Predictive value of single-nucleotide polymorphisms in curve progression of adolescent idiopathic scoliosis

PURPOSE

Genetic diagnosis is a promising approach because several single-nucleotide polymorphisms (SNPs) associated with adolescent idiopathic scoliosis (AIS) progression have been reported. We review the predictive value of SNPs in curve progression of adolescent idiopathic scoliosis.

METHODS

We reviewed DNA-based prognostic testing to predict curve progression. Then, the multiple polymorphisms in loci related to AIS progression were also reviewed, and we elucidated the predictive value of SNPs from four functional perspectives, including endocrine metabolism, neuromuscular system, cartilage and extracellular matrix, enzymes, and cytokines.

RESULTS

The ScoliScores were less successful predictors than expected, and the weak power of predictive SNPs might account for its failure. Susceptibility loci in ESR1, ESR2, GPER, and IGF1, which related to endocrine metabolism, have been reported to predict AIS progression. Neuromuscular imbalance might be a potential mechanism of scoliosis, and SNPs in LBX1, NTF3, and SOCS3 have been reported to predict the curve progression of AIS. Susceptibility loci in SOX9, MATN1, AJAP1, MMP9, and TIMP2, which are related to cartilage and extracellular matrix, are also potentially related to AIS progression. Enzymes and cytokines play essential roles in regulating bone metabolism and embryonic development. SNPs in BNC2, SLC39A8, TGFB1, IL-6, IL-17RC, and CHD7 were suggested as predictive loci for AIS curve progression.

CONCLUSIONS

Many promising SNPs have been identified to predict the curve progression of AIS. However, conflicting results from replication studies and different ethnic groups hamper their reliability. Convincing SNPs from multiethnic populations and functional verification are needed.

Lumbopelvic postural differences in adolescent idiopathic scoliosis: A pilot study

BACKGROUND

A primary etiology of adolescent idiopathic scoliosis (AIS) is currently unknown, but poor postural control of the spinal extensor musculature has been identified as an AIS risk factor. Identifiable postural differences would aid in advancing the precise postural behaviors that should be modified during Physiotherapy Scoliosis Specific Exercise (PSSE) to help limit the progression of AIS.

RESEARCH QUESTION

Are there any determinable differences in lumbopelvic posture or range of motion between subjects with AIS and controls?

METHODS

This prospective cohort pilot study consisted of 53 subjects (27 AIS and 26 control) aged 11-17 years. Subjects had their lumbopelvic posture assessed and monitored using the ViMove DorsaVi sensor package. All subjects underwent a live assessment to obtain initial lumbopelvic (LP) range of motion (ROM) measurements. Subjects were then monitored while continuing with normal activities of daily living (ADLs) for 12 h. With an alpha level of 0.05, nonparametric analyses were performed for each variable via a Mann-Whitney U-test.

RESULTS

During the live assessment, controls exhibited a significantly greater anterior pelvic tilt ROM in the sitting position than the AIS group (p = 0.0433). When compared to female controls, females with AIS had a sitting pelvic tilt ROM that was significantly more retroverted (p = 0.0232) and less anteverted (p = 0.0010). During ADLs, female controls exhibited a higher total number of extension events than their female with AIS (p = 0.0263). These associations did not strengthen with greater spinal deformity.

SIGNIFICANCE

This work demonstrates postural differences between patients with AIS and controls. Further study is necessary to determine why patients with AIS adopt these postures, and if PSSEs can be utilized to limit the progression of AIS.

Decreased cortical bone density and mechanical strength with associated elevated bone turnover markers at peri-pubertal peak height velocity: a cross-sectional and longitudinal cohort study of 396 girls with adolescent idiopathic scoliosis

Decreased cortical bone density and bone strength at peak height velocity (PHV) were noted in girls with adolescent idiopathic scoliosis (AIS). These findings could provide the link to the previously reported observation that low bone mineral density (BMD) could contribute as one of the prognostic factors for curve progression that mostly occurs during PHV in AIS.

INTRODUCTION

As part of the studies related to aetiopathogenesis of AIS, we assessed bone qualities, bone mechanical strength and bone turnover markers (BTMs) focusing at the peri-pubertal period and PHV in AIS girls.

METHODS

396 AIS girls in two separate cohorts were studied. Skeletal maturity was assessed using the validated thumb ossification composite index (TOCI). Bone qualities and strength were evaluated with high-resolution peripheral quantitative computed tomography (HR-pQCT) and finite element analysis (FEA).

RESULTS

Cohort-A included 179 girls (11.95 ± 0.95 years old). Girls at TOCI-4 had numerically the highest height velocity (0.71 ± 0.24 cm/month) corresponding to the PHV. Subjects at TOCI-4 had lower cortical volumetric BMD (672.36 ± 39.07 mg/mm³), cortical thickness (0.68 ± 0.08 mm) and apparent modulus (1601.54 ± 243.75 N/mm²) than: (a) those at TOCI-1-3 (724.99 ± 32.09 mg/mm³ (p < 0.001), 0.79 ± 0.11 mm (p < 0.001) and 1910.88 ± 374.75 N/mm² (p < 0.001), respectively) and (b) those at TOCI-8 (732.28 ± 53.75 mg/mm³ (p < 0.001), 0.84 ± 0.14 mm (p < 0.001), 1889.11 ± 419.37 N/mm² (p < 0.001), respectively). Cohort-B included 217 girls (12.22 ± 0.89 years old). Subjects at TOCI-4 had higher levels of C-terminal telopeptide of type 1 collagen (1524.70 ± 271.10 pg/L) and procollagen type 1 N-terminal propeptide (941.12 ± 161.39 µg/L) than those at TOCI-8 (845.71 ± 478.55 pg/L (p < 0.001) and 370.08 ± 197.04 µg/L (p < 0.001), respectively).

CONCLUSION

AIS girls had decreased cortical bone density and bone mechanical strength with elevated BTMs at PHV. Coupling of PHV with decreased cortical and FEA parameters could provide the link to the previously reported observation that low BMD could contribute as one of the prognostic factors for curve progression that mostly occurs during PHV in AIS.

The Influence of Surgical Correction of Idiopathic Scoliosis on the Function of Respiratory Muscles

Background and objective: It is important to introduce respiratory exercises to the therapy of patients after the surgical treatment of adolescent idiopathic scoliosis. Surgical correction is the best way to prevent hypoxia in scoliosis, but whether pulmonary rehabilitation increases the effectiveness of scoliosis surgery has not yet been confirmed. Therefore, the aim of the study was to evaluate the function of respiratory muscles after surgical correction of idiopathic scoliosis. Methods: The study involved 24 patients, aged 13.6 ± 0.6. Maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) were measured using the Mikro RPM. In all patients, before the procedure, 7 days after and 3 months after the procedure, the MIP and MEP were measured. Results: MIP was the lowest 7 days after the procedure; it was 45.28 cmH2O and was statistically significantly lower compared to the measurement before the procedure (p < 0.001) and 3 months after the procedure (p < 0.001). Conclusions: The degree of curvature of the spine before the procedure does not significantly affect initial values of the strength of respiratory muscles. The level of MIP is not dependent on the type of surgery.

Tent5a modulates muscle fiber formation in adolescent idiopathic scoliosis via maintenance of myogenin expression

OBJECTIVE

Paravertebral muscle asymmetry may be involved in the pathogenesis of adolescent idiopathic scoliosis (AIS), and the Tent5a protein was recently identified as a novel active noncanonical poly(A) polymerase. We, therefore, explored the function of the AIS susceptibility gene Tent5a in myoblasts.

MATERIALS AND METHODS

RNA-seq of AIS paravertebral muscle was performed, and the molecular differences in paravertebral muscle were investigated. Twenty-four AIS susceptibility genes were screened, and differential expression of Tent5a in paravertebral muscles was confirmed with qPCR and Western blot. After the knockdown of Tent5a, the functional effects of Tent5a on C2C12 cell proliferation, migration, and apoptosis were detected by Cell Counting Kit-8 assay, wound-healing assay, and TUNEL assay, respectively. Myogenic differentiation markers were tested with immunofluorescence and qPCR in vitro, and muscle fiber formation was compared in vivo.

RESULTS

The AIS susceptibility gene Tent5a was differentially expressed in AIS paravertebral muscles. Tent5a knockdown inhibited the proliferation and migration of C2C12 cells and inhibited the maturation of type I muscle fibers in vitro and in vivo. Mechanistically, the expression of myogenin was decreased along with the suppression of Tent5a.

CONCLUSIONS

Tent5a plays an important role in the proliferation and migration of myoblasts, and it regulates muscle fiber maturation by maintaining the stability of myogenin. Tent5a may be involved in the pathogenesis of AIS by regulating the formation of muscle fiber type I.

Dipeptidyl peptidase-4 is associated with myogenesis in patients with adolescent idiopathic scoliosis possibly via mediation of insulin sensitivity

Background

Abnormal metabolic features have been previously described in adolescent idiopathic scoliosis (AIS) patients. As an important regulator involved in energy metabolism, DPP-4 activity was reported to be remarkably decreased in osteoblasts of AIS patients. To date, there was still a lack of knowledge concerning the role of DPP-4 in the myogenesis of AIS.

Methods

Circulation DPP-4 level was assessed in the serum of 80 AIS girls and 50 healthy controls by ELISA. Myoblasts were purified from muscle specimens of AIS patients and LDH controls, and then treated with metabolic effectors including glucose and insulin. CCK-8 assay was used to assess the cell viability and myotube fusion index was calculated to evaluate myogenesis ability. Gene expressions of downstream signals of DPP-4 were evaluated by RT-qPCR and Western blot respectively.

Results

AIS girls had remarkably down-expressed DPP-4 in both serum level (0.76 fold) and tissue (0.68 fold) level. Treatment with metabolic effectors led to significantly increased DPP-4 expression in the control cells, while there was no increase of DPP-4 in AIS cells. CCK-8 assay showed that the proliferation rate of control cells was significantly increased after being treated. Remarkably higher fusion index was also observed in the treated control cells. By contrast, the fusion index and cell proliferation rate were comparable between the treated and the untreated AIS cells.

Conclusions

Our study suggested a potential role of DPP-4 in abnormal metabolic condition of AIS patients. Compared with control cells, AIS myoblasts presented obviously impaired sensitivity to the treatment of glucose and insulin. Aberrant DPP-4 expression could lead to impaired insulin sensitivity in myoblasts and further influence the cell viability during myogenesis. The molecular mechanism connecting DPP-4 and insulin-related signaling in AIS is worthy of further investigation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-02978-w.